There's an app called "ACR" that you can use to record conversations. https://apps.apple.com/us/app/acr-call-recorder-for-iphone/id1377904267
Yes and yes. Also, you may or may not need to advise the individual that they are being recorded. In my world, we see it frequently when an employee has recorded a conversation between themselves and a manager which results in some form of disciplinary action, in turn that recording comes to play in their meeting with me or they attempt to use it in court. Just because it is against policy, doesn't mean that it's not admissible in court. As well, many times conversations are recorded (sales calls, customer service calls, etc..) that are between states. You have to be very careful about what you want to accomplish when doing this. In your case, any bonus or supplemental compensation you would be due should be documented on Company letterhead or signed from a Company official. Otherwise, if it is a discretionary bonus, then it's optional for them to pay it out, or not to. If there is not an agreement in place, your likely looking at a civil case of he said/he said. Also, I highly recommend documenting all the inventory you have and taking pictures of it all leaving your possession. Do not attempt to hold said inventory for ransom.
Make sure you are in a single party state. If you are in a state where its two party, you need to disclose you are recording them. Find out here. http://www.expert-opinions.net/one-and-two-party-state-information/
Put everything in writing. Period. Keep it on a record. Recording phone conversations may be more problematic than helpful.